1. Identifying the Mobile Phase: In "Gas Chromatography" (GC), the mobile phase is always a
Gas. This gas (often called the carrier gas) must be inert, such as helium, nitrogen, or argon. Its function is to transport the vaporized sample through the system.
2. Identifying the Stationary Phase: The "Liquid" part of "Gas-Liquid Chromatography" refers to the stationary phase. In this setup, a non-volatile
Liquid is coated as a thin film on the inner wall of a capillary column or on the surface of an inert solid support material.
3. The Mechanism of Separation: Separation occurs because different components of the sample partition themselves between the moving carrier gas and the stationary liquid film at different rates. Those that are more soluble in the liquid phase move more slowly, while those that stay in the gas phase move faster.
Thus, in Gas-Liquid chromatography, the phases are exactly as the name suggests: a stationary Liquid and a mobile Gas.